Zivanic said: "Atmos nodes all have to be at the same exact code level in order to replicate data. If attempting to federate an Atmos private cloud with an external service provider using Atmos, such as AT&T, this becomes significantly complex to manage operationally. … How would a customer attempt to upgrade multiple nodes at petabyte-scale across several locations? … Atmos’ deficiencies are equivalent to one iPhone user not being able to contact another iPhone user because they were each running different versions of iOS."

EMC says this is plain wrong:

This is incorrect and a mischaracterization of the Atmos product. A customer can have different versions of Atmos software running in a single cloud. This is a requirement for cloud-scale deployments where there are often hundreds of nodes per data center and multiple data centers in a single Atmos system. A common approach for our customers is to upgrade one data center at a time. Therefore, they run in a mixed version environment for some period of time.

Secondarily, Atmos federation is the ability to connect a private Atmos deployment with one of many public Atmos service providers. Customers control this capability via Atmos data placement policies and use this capability to build a hybrid cloud spanning their private environment with a service provider’s public cloud. Atmos federation is agnostic to the software version. The only requirement is that the customer’s private cloud needs to be running Atmos 1.3 – the first version when federation was introduced.

We understand that Atmos is a scale-out architecture and no fork-lift upgrades or generation technology refreshes are required.

No need to freshen up

Atmos customers can mix newer nodes with prior generation nodes in the same cloud system. Technology refreshes and migrations are not required in order to use current generation hardware. Customers can continue to run with this type of implementation and/or over time replace earlier generation nodes with current generation nodes that will have denser drives, greater processing power and lower energy requirements. This is the customer’s choice and not a requirement.

One major premise of cloud compute and storage is that customers accessing public cloud resources no longer have to undergo data migration, datacentre maintenance or deal with products that have reached the end of their useful life. With Atmos, EMC says, the cloud service provider can use dissimilar versions in a federation and not have to undergo generational refreshes either.

There are public cloud services based on Atmos, such as Peer1, and Redstor in the UK. These compete with Nirvanix's cloud services.

EMC itself operates an Atmos-based development cloud for its prospects, customers, developers and service providers called Atmos Online. They can use this to develop their own private or public Atmos-based cloud like the Redstor one.

We take from this that, like iPhones, one Atmos system can talk to (federate with) another of a different generation. ®